The invention relates to a device for use in the inspection of luggage and the like by means of X-rays, in which rays from an X-ray flash generator are directed through the object to be inspected, to produce a shadow image on a fluorescent screen, which image is received by a TV camera, the video signals of which are supplied to an intermediate store. The video signals may then be supplied to a TV monitor. The X-ray flash generator, TV camera and intermediate store are operatively connected with one another over a suitable control unit.
The increase in terrorist attacks on installations of all types, in particular on airplanes and at airports, necessitates security measures in which a careful check of persons and their baggage is consummated. While a manual search is practical insofar as the quality of the inspection is concerned, it is time consuming and has the associated unpleasantness of necessitating the opening, examining and frequently rearranging of the contents of the luggage. Fluoroscoping by means of X-rays presents a quick and sure examination of luggage as to weapons, ammunition and the like, but in such process other problems arise and must be considered, in particular the problem with respect to the environment and the baggage contents, for example, film which must not be endangered or damaged by X-rays.
A method and device for revealing dangerous objects and/or valuable metals or the like by means of X-rays, whereby an object is radiated with X-rays which, following penetration through the object involved, are suitably collected to effect a visible reproduction, is for example, illustrated in U.S. Pat. No. 3,844,816. The method involved is characterized in that by means of accelerated electron beam, an anticathode is constantly scanned or is irradiated in a coarse pattern by means of focal spot scanning and the X-rays produced in such manner are directed at an object. In addition that part of the object having a comparatively high X-ray absorption is monitored by means of the collected X-rays and an exact X-ray permeability image of the part of the object with comparatively high X-ray absorption is produced. In addition to the fact that in this known method, with a constant scanning, either film damage or an extremely fuzzy, unclear pictures must be contended with, an expensive scanning signal generator and/or a transport means for moving the object to be examined at a set speed is required.
U.S. Pat. No. 3,678,278 illustrates another luggage inspection apparatus in which the luggage to be examined is placed in a stationary manner on a platform over which an X-ray shielding hood is moved into place. With the shielding hood in a closed position the piece of luggage is fluoroscoped by means of X-radiation emanating from an X-ray generator to produce a shadow image of the fluoroscoped piece of luggage on a fluorescent screen. With a structure employing a housing of this type, switching means is provided to preclude an operation of the X-ray generator with the shielding hood in open position. In addition, provision is made for enabling the shadow image produced on the fluorescent screen to be observed by means of a connected TV circuit. While this arrangement, on the overall basis, does offer an effective protection of the environment from X-radiation, it operates with a continuous X-radiation which with the necessary intensity for a sufficiently sharp shadow image, leads to film damage, and thus is not film-protective.
In order to limit the damaging influences resulting from X-radiation to a minimum, luggage inspection installations have been produced which operate with flash-type X-ray operation, whereby the X-ray dosage can be limited with respect to both time and intensity, whereby the damaging influences resulting from X-radiation can be limited to a minimum. The shadow image of the inspection object produced by the X-ray flash generator is picked up by the highly sensitive TV camera and entered into a store, from which the shadow image can be read out on a TV monitor for as long a period of observation as desired. Such a system presupposes that the X-ray and the TV camera are precisely synchronously switched on. Heretofore this was possible only with a field emission X-ray flash tube, since only a flash tube of this type is triggerable by the pulse signals of the normal pulse generator of a TV camera. However, field emission X-ray flash tubes have a very short life-span of approximately 2,000 to 30,000 flashes per tube so that the baggage inspections installations of this type imploying an X-ray flash generator have unacceptably high replacement part costs.